


Cake or Death

by johnwatsonswindmachine



Category: Sherlock (TV)
Genre: Case Fic, Mystery
Language: English
Status: Completed
Published: 2012-05-07
Updated: 2012-05-28
Packaged: 2017-11-05 00:25:09
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 6
Words: 7,658
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/399856
Author URL: https://archiveofourown.org/users/johnwatsonswindmachine/pseuds/johnwatsonswindmachine
Summary: <blockquote class="userstuff">
              <p>A prominent solicitor drops dead from an apparent stroke, but Sherlock is sure it was murder. Spoiler alert: It is.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> This is my first fic, and I'm cross-posting from fanfiction.net. When I started, I thought it would be 3 - 4 chapters long, but it seems that it's growing. I try to post once a week, but life has been extra life-y lately so it's kinda turned into every other week.

The tension in the flat was palpable, the silence broken only by the quiet clink-clink-clink of John stirring his much-needed tea. The cream and sugar had been sufficiently blended about a minute ago, but still John stirred, hoping the repetitive movement would clear the anger from his head. So far, no luck.

"I still don't see what the problem is." Sherlock's voice cracked the stillness, and John gave up on calming down.

"The problem, Sherlock -" John managed to make Sherlock's name sound like a horrible insult. "The problem is that you just told a new father that his baby is, in fact, his best mate's baby. In front of 20 people."

"It's important information. I assumed he'd want to know. And I don't see how the amount of people in the room influences anything."

John sighed. No, of course he wouldn't. He was going to have to explain, wasn't he? Explain to his genius flatmate why gleefully destroying a marriage in front of a crowd of spectators was, to put it lightly, a bit not good. Again.

John was arranging his thoughts into a slightly less caustic form when Sherlock's phone pinged. Sherlock leapt up from the sofa, hurdled the coffee table, and promptly tripped on the mess of papers strewn about the living room. He had barely hit the floor before he bounced up again and snatched up his phone, ignoring John's laughter.

"Shut up, John. We have a case." Sherlock swooshed off to his room to get dressed, stepping over the hysterical form on the floor that was Dr John Watson.

...

It was one of the nicer crime scenes they had seen. To John, it was because of the sophistication of the flat, the expensive modern decor, the way you could almost smell money when you crossed the threshhold. To Sherlock, it was because of the stark white color palette, the plush carpet that held footprints almost as well as mud, and the overabundance of glass surfaces. It was a forensic wet dream.

The flat belonged to Dr. Anthony Richardson, psychiatrist, though at the moment, Dr. Richardson would have been much more convincing as a patient.

"We were having a coffee, talking about whether I should appeal, and then he said his head was killing him, so I went to get him some paracetamol, and when I came back he was having a seizure. I dialed 999, and he started to come round, but then he just collapsed again and when the paramedics got here it was too late and and oh god I just can't believe it!" Richardson was practically clinging to Sgt. Donovan, who had all but given up on getting the overwrought man to answer her questions coherently.

John and Sherlock joined Lestrade at the far end of the foyer, just outside the open door to the living room. Lestrade was leaning against the wall, watching Richardson. "Look at the poor bastard. He's an absolute wreck," said Lestrade.

"I'm assuming he and the victim were close?" asked John.

Lestrade pushed off from the wall and turned to face John and Sherlock. "Well, I don't know about using the word 'victim' just yet, but yeah, they were close. Him and Dorset - that's the deceased - go back about 6 years. Dorset was a fairly well-known solicitor, did mostly malpractice suits, defending doctors and whatnot. Won most of 'em, too. His last case was Richardson's - a family suing for wrongful death after their daughter committed suicide. Richardson lost the case and had his medical license revoked."

Sherlock hummed and then, apparently finished with his observation of the inconsolable psychiatrist, strode to the door of the living room, eyes roving, absorbing, cataloging, sorting data into relevant and irrelevant.

_Almost rectangular room, roughly 9x6 meters, walls Parisian plaster, white. Doorway to foyer set at an angle to southern and western walls. Second doorway midway along southern wall, far western wall opens onto kitchen. High ceiling, eastern and northern walls all windows. Scattering of irrelevant paintings and vases and such. Carpet throughout, wool, white, irregularities in the pile indicating footfall or, in this case, body fall. Coffee table, rectangle, 1x1.5 meters, glass - excellent, prime surface for prints. Two sofas, each running parallel to the table's long sides, also white, suede - oh god, suede, this must be Christmas - disturbances in the grain - there, where each man sat, Richardson facing the door, Dorset with his back - and there, where Dorset fell. Dorset himself, on his back, dragged a short distance from the couch and sofas._

Sherlock stepped forward, knelt down next to the dead man.

_35 - 40, 5' 11", about 175 pounds. Well-muscled, especially in arms, touch of calluses on his palms - from a racket? Yes, tennis. Expensive trousers, tan, and shirt, light blue. Gold wedding band, clean, also expensive. Three small coffee stains on his right thigh - must have spilled some while drinking. A trace of cake crumbs around the mouth - cake and coffee with Richardson, then._

"Can you give me a cause of death, John?" Sherlock asked, looking up. John joined him next to the body, checking the airway and pupils, sniffing the mouth, examining the skin for punctures. "Not asphyxiation, not any form of trauma," "Obviously," huffed Sherlock, but John ignored him and continued. "My guess is a heart attack or stroke, but I can't be sure until there's a proper post-mortem." Sherlock nodded his approval, then turned to Lestrade. "Has anyone touched anything?"

"Richardson was holding Dorset when the paramedics came in, but they dragged him off. They checked Dorset's vitals and confirmed that he was dead, then went to the foyer with Richardson and called us." Lestrade looked vaguely proud that his fellow civil servants had managed to not contaminate a crime scene. Sherlock crinkled his brow slightly, then strode off to the kitchen.

_Square, 6x6 meters. Cream marble floor, black cabinets lining the north wall and south walls, cream granite worktop. Refridgerator on west wall, 1x2 meter island, also black with cream granite top. The usual kitchen appliance, all stainless steel. Fruit bowl, dish towel, accents - irrelevant. What's missing? Dishes. Dishes from coffee._

Sherlocked strode over to the sink, peering at it closely, running his hand over the basin. _Dry._ He stepped over to the dishwasher and opened it. A puff of steam wafted over his face as he reached in to touch the dishes. _Warm. Condensation. Cycle not yet complete. Cycle length for this model: 1 hour, 45 minutes._ Sherlock straightened. "When did the 999 call come in?" Lestrade flipped a page in his notebook and scanned the writing. "Uhhh... 5:36, ended at 5:41." "And when did the paramedics arrive?" Lestrade consulted his notes again. "5:46." Sherlock glanced at his watch. _7:13._

"I'll take the case."


	2. Chapter 2

**Summary for the Chapter:**

> In which John and Sherlock interview a witness and Sherlock deduces things because Sherlock.

**Notes for the Chapter:**

> Since chapters 1 - 5 are posted at fanfiction.net, I'm posting them here all at once.

"You really think it was murder, then? He couldn't have just had a heart attack or stroke like John said?" Lestrade looked at Sherlock hopefully, which was probably inappropriate for a DI.

"I don't think; I know," Sherlock said curtly. "Am I correct in assuming that Richardson is still present?" Lestrade nodded distractedly and waved in the direction of the foyer with his left hand, running the right over his face with a sigh. Great. Another high-profile death that the Chief Inspector would want closed right away, before they managed to screw up their press relations even more. Another seemingly open-and-shut case that Lestrade would have to fight to keep open. Why couldn't important people just die naturally? It seemed rather showy of them, insisting on a sensational death.

John followed Sherlock into the foyer. Richardson was seated on the steps, much calmer than before. He had the ubiquitous shock blanket draped around his shoulders and was sipping a cup of tea. Richardson looked up as John and Sherlock approached, glancing between the two, as if trying to ascertain why these two – obviously not public servants – were here, and why the tall, angular man was looking at him like that, like an art critic appraising a newly discovered Rembrandt.

Sherlock paused for fraction of a second, choosing an approach – sympathetic or aggressive? Polite or harsh? Familiar or clinical? Direct or circuitous? – then, having made his choice, walked in front of Richardson, looming over him. "Dr. Richardson," Sherlock said by way of opening, placing emphasis on the first word. "Psychiatrist, yes?"

Richardson nodded, swallowed. He rose to his feet, clearly uncomfortable with the severe height dichotomy Sherlock had created. Not the right tack, then. Sherlock gentled his face and stepped back. He needed Richardson calm.

"DI Lestrade tells me you and Dorset were close?" Richardson nodded again and spoke for the first time. "We met about six years ago, though work. He needed an expert witness for a wrongful death case. He kept coming to me for advice on psychiatric cases, and eventually we became mates."

"And he defended you when you were charged with malpractice?" Sherlock prompted. Richardson met Sherlock's eye, blinking rapidly. "Yes. He did a wonderful job, best I could have hoped for." Sherlock's eyes narrowed slightly. "So you don't blame him at all for the loss of your license?"

Richardson look like he'd been slapped. "What? Of course not! He was my best mate! How the hell could you think –" Sensing they were about to lose Richardson to another fit of agitation, John stepped forward and put a calming hand on the man's arm. "No, no, we don't think that. We just have to ask these questions. I'm sure you can understand," he said soothingly. Richardson looked back at Sherlock, who nodded his agreement. Richardson deflated, swallowing hard as he wrapped his arms around himself and stared at the ground. "Of course, of course," he murmured.

John glanced at Sherlock, who nodded slightly. Best let John take this one – he did better with the emotional ones. Bedside manner and all that.

"Dr. Richardson? I don't think I introduced myself properly. I'm John. I'm working with The Yard to figure out why this happened to your friend. Can you tell me what happened?" John's voice was soft, gentle, and Richardson relaxed under it. Sherlock was reminded briefly of mother calming a child.

"Tim – that's his first name – came round to talk about appealing my case. We were sitting in the living room, having a coffee. He said his head was killing him, so I went to get him some paracetamol. When I got back he was on the ground having a seizure. I called 999, and he came round for a bit, but then he collapsed again, and by the time the paramedics arrive it was too late."

"Did he have any medical conditions? Epilepsy, heart disease?" John asked, still gentle, comforting. Richardson shook his head. "And you attempted to resuscitate him, correct?" interjected Sherlock, matching John's tone. "Yes, I tried to resuscitate him," replied Richardson, looking again at Sherlock.

"One more question, Dr. Richardson, before we go: Did Mr. Dorset consume anything besides coffee while he was here?" Sherlock voice had lost its softness, and he was studying Richardson again, eyes once more sharp and expectant.

Richardson looked up and met Sherlock's eyes steadily, pausing slightly. "No, just the coffee. He had just the coffee."

Sherlock lifted his head slightly, rocking back onto his heels. "I see," he murmured, then turned sharply on his heel and strode out the door of the flat, leaving John to thank the psychiatrist, awkwardly pat his arm, and offer some trite condolence before hurrying after Sherlock.

…

Sherlock was standing impatiently beside a cab when John caught up with him. John was starting to wonder if Sherlock had some sort of bat signal for cabbies – come at once, Sherlock Holmes is on the move. Either that or the cabbies had learned to follow him for a sure fare. Probably a more likely answer.

"Where to now? Bart's?" asked John as he slid into the cab next to Sherlock and shut the door. "No, I think Molly can handle the autopsy. I've told her to run a full tox screen, as well as tests for any other medications, and to save the stomach contents for me. While we're waiting, we may as well go see Dorset's widow," said Sherlock distractedly as the cab pulled away from Richardson's building.

John and Sherlock sat in silence for a few minutes, each absorbed in thought. Sherlock, obviously, was thinking about the case, sorting through information, calculating probabilities, running and re-running possible scenarios. John, too, was thinking about the case, but he was more focused on why Sherlock had taken it. To John it seemed to be an unfortunate but perfectly natural death. Sherlock was clearly suspicious of Richardson, but again, why? John was certain he was missing something vital. He was tempted to ask Sherlock, but decided against it. It would be nice to work this one out on his own, and besides, he knew better than to interrupt Sherlock when the detective was this deep in thought.

John's train of thought was derailed by Sherlock's voice. "The dishes, John. It was the dishes." He sounded mildly condescending, which, for Sherlock, was a compliment.

"The what now?" John wasn't following. So much for working it out on his own. Oh well; maybe next time. Sherlock gave John his patented how-does-your-brain-work look, tempered slightly by his I-get-to-show-off-now smile, and launched a rapid volley of deductions.

"They were having coffee when Dorset fell ill – Richardson said that specifically, once to Donovan and once to us. But there were no dishes in the living room. There were, however, half-washed dishes in the dishwasher – two mugs, two salad plates, one dinner plate, two teaspoons, two forks, and one cake server. All the dishes they would have used." Sherlock was building up steam, rattling off facts like a machine gun does bullets.

"But Richardson said they just had coffee," interrupted John, earning an annoyed look from Sherlock.

"Really, John, I expect better of you by now. Did you not observe the cake crumbs on Dorset's mouth? Of course they had cake – a cake which had mysteriously disappeared by the arrival of the paramedics. And then there's the dishwasher!" Sherlock was excited now, thrilling in the chance to show off.

"That dishwasher has a cycle time of one hour, 45 minutes, and is started by a circular dial that moves as the cycle progresses. If we compensate for the five degrees placed between the labeled start of the cycle and the labeled end, the dial must travel at a rate of 3.38 degrees per minute. When I opened the dishwasher, the dial had traveled approximately 300 degrees from the marked start, meaning the cycle had been running for 89 minutes. I opened the dishwasher at 7:13, which places the starting time at 5:44 – three minutes after Richardson got off the phone with 999 and two minutes before the paramedics arrive. Now why would a man, upon seeing his 'best mate' collapse, leave his friend to wash the dishes? Hardly the normal response."

"And then there's his pathetic attempts at deception when we spoke to him – don't look at me like you're surprised, it was obvious! He told us the exact same story he told Donovan, with almost the exact same words, when you asked what happened. He repeated my words back to me exactly when I asked him if he had attempted to revive Dorset, but you saw the body, the ribcage is perfectly intact, so either Richardson didn't know how to perform CPR – unlikely, given that the man's a doctor – or he didn't attempt to revive Dorset at all. The rapid blinking, the dilated pupils, the slightly delayed response when he told us Dorset had only had coffee, the overblown anger when asked if he blamed Dorset for losing the lawsuit, repeatedly looking down and left – universal sign of shame and guilt, John, learn that – all these things, when taken together, give the clear indication that Richardson was lying."

"'But Sherlock," the detective mimicked, his voice sing-song, "he was in shock! His best friend had died!' No, John, he was not in shock; he was doing an impression of shock – unfortunately, not a good one. People in shock don't look at you when they're in shock; they look through you. The thousand-yard stare, they call it. Richardson, on the other hand, made direct eye contact when telling me about his resuscitation attempt and the coffee – checking to make sure I was believing him. Another hallmark of deception, though contrary to popular opinion – which is a gold star on a hypothesis in its own right, I've found. No, Richardson was lying alright, and when we add in the business with the dishwasher, there's only one plausible conclusion: Richardson poisoned Dorset."

And John once again gave up on deducing the answer to any question more complicated than whether or not the milk was spoiled.


	3. Chapter 3

Sherlock drummed his fingers on the cab door, staring absently at the London traffic, seeing but not observing. Talking to Dorset's widow had been disappointingly uneventful – she was clearly innocent, and Sherlock had observed nothing of significance in the house itself – and the meeting had stretched out interminably. He couldn't help but wonder if he should have skipped it entirely in favor of the autopsy. The murdered man's stomach contents were likely to be crucial to the case, and listening to Jenny Dorset dither on about her husband did nothing to stop the corrosive action of hydrochloric acid on Dorset's cake and coffee.

Sherlock shot out of the cab as soon as it pulled up to the curb at Bart's. John paid the cabbie quickly and followed close on Sherlock's heels, both men power-walking to the morgue. They burst in unceremoniously, causing Molly to start with a little yelp.

"Stomach contents. Where are they?" Sherlock's voice was clipped.

Molly stepped away from the corpse, giving Sherlock and John a better view. The body had been cut open in a Y-shape, and the ribs had been open and folded upwards to reveal the chest cavity. A tray next to Molly held the majority of Dorset's organs. Molly gestured to a stainless steel bowl. "It's right there, I was just about to close him up and start on the cranium."

"Good," said Sherlock briskly. "You dissect the brain. John, you take the heart. I'll take a look at the stomach contents. First one done runs blood and tissue tox screens. We'll start with the usual substances, but be sure to keep enough samples just in case." Without further ado, Sherlock grabbed the stainless steel bowl that held Dorset's stomach and swept into the adjacent lab.

John moved over to the tray and found his assigned organ. "Find anything yet?" he asked. Molly shook her head. "Everything looks picture-perfect so far." She picked up a saw from the tray, and John took it as his cue to join Sherlock in the lab. Removing a skullcap was messy business, and he wasn't exactly dressed for an autopsy.

Sherlock had already removed the contents of Dorset's stomach and was taking samples, putting some on slides and sealing others for future testing. Neither man talked as they went about their work, focusing completely on their tasks.

The minutes passed, punctuated only by occasional annoyed huff from Sherlock's side of the lab. Eventually John stepped away from the countertop that held Dorset's heart. "Found something?" queried Sherlock, cocking his head. "I'd give cause of death as a heart attack, probably secondary to a hypertensive crisis," said John. Sherlock frowned a bit, then shook his head. "Alright, start in on the tox screen then."

After a few more minutes, Molly came in with her results. "So far I've found an intercranial hemorrhage over the left parietal lobe." "Hypertensive crisis?" asked John. Molly nodded. "It's strange," she said. "He didn't have any signs of chronic high blood pressure, and he doesn't have any risk factors for such a sudden spike," She frowned a bit, unconsciously mirroring John and Sherlock.

"Well, it looks like we've got a long night of tests to run," said John. "I'm going to run down to the mess to get some food. Anyone wants some crisps?"

...

It was nearly 12 hours later when Lestrade arrived at the lab. John was leaning over a centrifuge, attempting to yawn and drink coffee at the same time. Molly appeared to have fallen asleep with her face resting on the eyepiece of a microscope. Sherlock, of course, looked as if he had just woken after a full night's sleep. Who needed sleep when you had adrenaline?

"So what do you have, Sherlock?" John and Molly jumped a bit at the sudden voice. Sherlock didn't look up from his microscope. "Intercranial hemorrhage and myocardial infarction, both secondary to hypertensive crisis."

Lestrade paused for a moment, processing. "So in English...?" John smiled a bit. He had trouble keeping up with Sherlock, and he was a doctor. He could only imagine how Lestrade felt. "He had a heart attack and a stroke because his blood pressure spiked suddenly," John supplied.

"Oh, okay." Lestrade's face clouded. "Any luck on the tox screen?"

Sherlock kept his face down in his microscope as he answered. "Nothing so far, but I'm confident a more extensive test will provide the necessary information. They'll take some time to run, but between the three of us," Sherlock gestured to John and Molly, "I'm sure we'll be able to get them done in a week or so." John and Molly groaned. Extensive tox screens normally took several weeks to complete; if Sherlock expected them to finish the tests in a week, it was clear they wouldn't be sleeping. "Oh, don't give me that," said Sherlock to the pair. "A man's been murdered; surely catching his killer is more important than whatever trivial things you would otherwise do with your time."

Lestrade shifted where he stood, hands in his pockets, looking uncomfortable. Sherlock's eyes snapped back to the DI, reading the slump of his shoulders, his nervous chewing on his lip. Sherlock's eyes narrowed. "What is it?" It sounded like an accusation.

"Well, the thing is, it's like John said. He had a heart attack, or stroke, or I guess both? Either way, the tox screen didn't turn anything up, and we didn't find any poison at Richardson's. It looks like a natural death, Sherlock, and I believe you when you say it's not, but the Chief wants to close this one as soon as possible– prominent citizen and all that. I'm sorry, Sherlock." Lestrade really did look sorry. He knew there was something off about this case, and while he couldn't put a finger on it, he knew Sherlock could, if he was just given time. But the Chief had refused to budge, and Lestrade's hands were tied.

"What? No!" Sherlock finally looked up. "There's no reason why Dorset would suddenly have a heart attack or stroke, let alone both, and the fact that you found nothing at Richardson's flat means nothing, given the calibre of your forensics team. The obvious answer is that Richardson used a substance that he knew wouldn't show on a standard tox screen. He's a medical man; he knows what wouldn't show up on the tests and he has access to a full pharmacy. He's counting on us giving up now, don't you see?" Sherlock grew more agitated with each word. Richardson had worn his guilt like a shock blanket, and the fact that Dorset had appeared to die of natural causes only fed Sherlock's interest in the case.

Lestrade sighed. "I know, Sherlock. If I could, I'd keep it open. The whole thing feels funny to me. But I can't, Sherlock. I just can't. I'm sorry. The case is closed."


	4. Chapter 4

**Summary for the Chapter:**

> In which Sherlock, Molly, and John do science.

It had been an exhausting week, but they'd managed it. By working 'round the clock for roughly 170 hours, Sherlock, John, and Molly had managed to complete toxicology tests that normally took upwards of a month. 170 hours of staring into microscopes, of careful pipetting, of whirring centrifuges and Western blots and a slow elimination of possibilities.

And it had all been for nothing. _(Wrong wrong it must be wrong.)_

Sherlock stared at the results of the last test, the very last, the last possible solution to the murder of Tim Dorset. _(Wrong wrong how could I be wrong?)_

Negative. _(Wrong wrong oh god I'm wrong.)_

Sherlock narrowed his eyes. "This is impossible. You must have messed up the test." John barely restrained an angry sigh. "We've run it three times now, Sherlock. All of them. There's nothing."

"Then you must have missed something!" Sherlock bellowed, now pacing the lab frenetically, hands scrubbing through his hair. _(I must have missed something, I missed something, I'm wrong, I'm wrong, oh god, I'm wrong.)_

Neither John nor Molly seemed the slightest bit put off by Sherlock's sudden explosion. They had been at this for a week, with barely any downtime. They were all running on crisps and coffee at this point. Sherlock hadn't left the hospital, and John and Molly had only left for an hour, each going to their respective flats to bring back toiletries and fresh clothes. A spare gurney that had been wheeled into the lab was the closest thing any of them had seen to a bed the whole week. They slept in shifts, one at a time, two people always awake, always busy, always searching for something, anything.

But still, nothing.

But they all knew there had to be something. Sherlock's reasons for doing so were obvious, but John and Molly weren't just following him blindly. There was something off about all this. The two doctors knew Dorset shouldn't have had a stroke and a heart attack. If it had been one or the other, they would have been able to write it off as idiopathic – one of those strange flukes that struck mortals down every day. But both? At the same time? While in the presence of Richardson, whose behavior was, to put it lightly, so peculiar? It hardly seemed probable.

John nodded. "Right. So nothing in the blood or tissues. Nothing in his medical history. Nothing in the stomach contents. Where do we look now?"

Sherlock stopped his pacing and half-turned toward John, one arm crossed over his chest to hold his own elbow, worrying his fingernails with his teeth. "Hmm?"

"Where do we look?" John repeated himself. "We're all in agreement here; the man certainly didn't die of natural causes. So where do we look to find proof?"

"What if we stopped looking for something specific?" Molly had lost some of her usual hesitancy to speak somewhere along the past seven days. It had been awkward – she had been awkward – at first, but by now she was just too tired to care that both men had swung around to look at her, or to shrink away from the piercing look Sherlock was directing at her.

"We've got it in our heads that whatever we're looking for is on that list," She gestured to a whiteboard listing over a hundred chemical compounds, all of which had been crossed off. "But maybe it broke down before we could test for it, or maybe it's something else."

"Something else? It's an incredibly extensive list, Molly. What exactly would this something else be?" Sherlock snapped. But Molly wasn't fazed. "I don't know. But what if we just looked at the samples, like under a microscope, and maybe we'll find something off? You know, observe and all that."

Sherlock found himself in the uncomfortable position of realizing that Molly had an excellent idea, and worse, she had thought of it before he had. He shook his head, willing the thoughts away. "Alright, fine." With that, they divvied up the small amount of Dorset's blood, liver, and stomach contents they had left, and each went to their microscopes.

Thirty-seven minutes and 5 slides of Dorset's last meal later, Sherlock suddenly took his slide over to the scanning electron scope that would allow him a much closer view of the evidence. "Find something?" John asked. "Maybe... not sure yet." Sherlock muttered distractedly, fiddling with the dials of the scope.

He finished his adjustment and peered into the eyepiece, examining the individual molecules of his slide, making a mental list. _(Caffeine – from coffee, obviously. Sucrose – sugar from the cake, possibly coffee as well. Egg protein – cake. Gluten – flour from cake. Theobromine – chocolate cake, then. Sodium chloride – table salt, that goes in cakes, doesn't it? Lactose – milk. Soy protein and tyramine – from tofu. What is tofu doing in a cake?)_

Sherlock voiced his thoughts aloud. "John, you bake. What would tofu be doing in a cake?"

"Huh? Tofu in a – I do not bake! I cook. There's a difference." John glared at Sherlock, who rolled his eyes. "Okay, fine, you cook. But the question stands: Does tofu go in cakes?"

"Umm, no," Molly chirped. "Obviously." She laughed nervously, suddenly realizing that the detective may not like the fact that she had turned his favorite retort against him. But John spoke before Sherlock could respond. "What else is in there?"

"Hm? Oh, the expected things – caffeine from the coffee, sucrose, lactose, milk and egg protein, tyramine, traces of flour and sodium chloride, theobromine – all from the cake – and of course stomach acid."

John furrowed his brow. "Tyramine... why does that ring a bell?" Sherlock rolled his eyes. "Oh, I don't know, maybe because it's an amino acid and therefore has probably been mentioned to you once or twice in your medical training. Or one would hope."

John glared at him. "No there's some sort of thing, about not eating tofu and too much tyramine and some sort of reaction..."

The men froze. Their eyes met, and realization dawned on both. "Oh, brilliant, John, that is brilliant!" Sherlock's frustration had vanished, and he had morphed into a perfect impersonation of a child on Christmas morning. John smiled wide. "It really is, isn't it?" John agreed.

"What is?" Molly looked between the two men, thoroughly confused.

"Tyramine, Molly!" Sherlock exaulted. Molly looked at him blankly. Sherlock stepped forward gleefully and put his arms on her shoulders. "Think! We know Dorset and Richardson gave each other professional advice. And what is Richardson? He's a psychiatrist! And what condition makes up a significant portion of a psychiatrist's practice?"

Molly stared for a second, not sure if she was supposed to answer, or if Sherlock was just being especially dramatic. "C'mon, Molly, think!" Molly hazarded a guess. "Uh, depression?"

"Yes!" cried Sherlock. "And what does a psychiatrist do for depression? Well, he prescribes anti-depressants of course. Most likely an SSRI like Prozac, but what if he had it in for one of his patients? What if instead of something safe, he prescribed Dorset an MAOI, a depression medication that carries the risk of severe side effects, possibly even death, if the patient eats even a small amount of anything rich in tyramine – for example, tofu? What if Richardson, blaming Dorset for losing the malpractice case, slipped tofu into an otherwise innocuous cake, knowing full well it would set off a devastating reaction in Dorset's brain that would cause his blood pressure to rocket until his blood vessels burst and his heart gave out? Don't you see? It was murder! Brilliant, beautiful, clever murder!"

"But.. but.. there's no record of depression in Dorset's file, and he wasn't on any medication," Molly said, internally cursing her voice's waver.

"Oh, that's just a detail! Now that we know what to look for, it will hardly be difficult to find record of Richardson giving Dorset the medication!" Sherlock twirled around in place, then swooped over to the make-shift bed in the corner to grab his coat and scarf as John shrugged his jacket back on. Suddenly all exhaustion was forgotten in the thrill of the chase.

Molly goggled at the men as they rushed out of the room. Some people just had all the fun.


	5. Chapter 5

**Summary for the Chapter:**

> In which all that crazy science is explained, and Sherlock has some sketchy plans for John. No, not in that way. I'm not a good enough writer for that.

**Notes for the Chapter:**

> This chapter brings us up-to-date on everything I've written so far. I'm hoping to get chapter 6 up soon - as in, I'm going to try to write it today - but I can't be entirely sure my brain will cooperate with me.

"So you're saying Dorset was poisoned." Lestrade leaned back in his desk chair and crossed his feet on the desk.

"In a manner of speaking, yes," said Sherlock. The detective had the flushed look of triumph about him, but it was quickly becoming contaminated by the frustration of being surrounded by idiots.

"And the poison was in the tofu, which, for some bizarre reason, Richardson put in cake?" Lestrade was used to wild theories, but this one just wasn't adding up to him. Yet.

"No, no, the poison was the tofu!" Sherlock jammed his hands into his hair, scrubbed furiously, and looked at John for help. John took his cue from there.

"We're working on the theory that Dorset was depressed, and that he'd gone to Richardson for help." John held up his hand to still Lestrade's protests. "I know, I know, there's nothing on his charts. We'll get to that." Lestrade nodded and settled back into his chair, ready for story time with Dr. Watson.

"If he was depressed, he'd be on anti-depressants. Some anti-depressants have deadly reactions with foods, so you have to be really careful about what you eat. Nothing cured or fermented – no wine, no beer, no aged cheese or smoked meats. Tofu's fermented, so it's right out too."

"And there was tofu in the cake... you're saying Richardson knew what Dorset was taking and put tofu in the cake to set off that fatal reaction?" asked Lestrade. John nodded. "Basically, yes."

"Well why the bloody hell couldn't you have just said that?" Lestrade huffed at Sherlock. The detective in question stopped his pacing and stared at Lestrade, mouth agape. "I did say that. That's exactly what I said."

Lestrade laughed. "No you didn't. You went off on this medical mumbo-jumbo rant about brain chemicals and Tylenol – " "Tyramine," muttered Sherlock. Lestrade waved his hand. "Whatever. Point is, that is most definitely not what you said."

Sherlock rolled his eyes and inhaled, ready for a splendid "Oh your tiny minds, however do they work?" rant, but John was quicker. "Alright, alright, it doesn't matter. The thing is, detective inspector, we know how Richardson did it now, so surely you can re-open the case." John planted himself in front of the DI's desk, arms crossed, frowning down at Lestrade as well as his height would allow him. It didn't do the trick.

"Well, no, I can't. It's a lovely theory," "It's not a theory! If anything it's a hypothesis, but we have significant supporting data," scoffed Sherlock, but Lestrade continued on as if he hadn't heard anything. "But it's not enough. According to his record, he's never even been to a psychiatrist, let alone been prescribed anti-depressants. I bend a lot of rules for your deductions, Sherlock, you know I do, but I can't bend here. The case is still closed." Lestrade looked at Sherlock. "Were any new evidence to come to light, of course, the case would be re-opened."

A slow smile spread over Sherlock's face as he looked back at the DI. "Of course. Well, Lestrade, John and I must be off – pressing engagement, simply can't be late – but I'm sure we'll be in touch. Come along, John." With that Sherlock swooped out of Lestrade's office and down the hall toward the lifts. John nodded his goodbye to Lestrade and hurried after Sherlock.

"So what's this pressing engagement of ours? I was under the daft impression that I might be able to finally sleep." John said as they stepped into the lift. John certainly hoped he would be able to sleep. He had pulled enough all-nighters in med school and Afghanistan, thank you very much, and now he was frankly too old for this shit.

"Hm?" said Sherlock, taking the thumbnail he had been worrying out of his mouth. "Oh yes, I suppose you can. 9:30 pm is probably considered an unacceptable time for an unexpected visit to the newly widowed. Isn't it? You'd know better than I; you're the one that fills your brain with these social niceties. No matter. We'll go in the morning." Sherlock smiled in a way that was more than a little maniacal. "After all, we want you looking your best!"

The lift emptied quickly.

oOo

The morning dawned bright and fresh and cliched. John sat at the table with his tea and toast, reading over the newspaper, while Sherlock drank his coffee and fiddled with John's laptop. Neither man looked up at the familiar "Yoo hoo!" of Mrs. Hudson.

"Oh hello boys! I haven't seen you about the past week. Been on a case, have you?" The not-housekeeper puttered about, putting the milk back in the fridge and wiping up Sherlock's spilled coffee grounds.

John nodded without looking up from his paper. "Yeah, with that dead solicitor that's been all over the news. His best mate killed him. With cake." John took a sip of his tea, acting as if what he had just said was perfectly normal breakfast conversation, because – at least in 221B – it was.

Mrs. Hudson hummed appreciatively as she put a piece of toast on a plate. "Well, that was creative of him. Must've gotten the recipe from Mrs. Turner." Mrs. Hudson dropped her voice to a conspiratorial whisper as she placed the toast in front of Sherlock. "Poor woman couldn't bake a pound cake to save her mother's life," she said from behind her hand. John just nodded.

Sherlock picked up the toast and munched on it absently as he scrolled through his Google search results. Dorset's widow, Jenny, had quite the public life. Of course, most of what Sherlock was finding was information he had deduced when he first met the woman in question, but there were a few things he hadn't known – such as the fact that she had previously been engaged to her husband's killer. Funny how she had failed to mention that. Sherlock shut the laptop with a snap. "Finish your breakfast, John. You're going to be late for your date."

Mrs. Hudson cooed. "Oooh, how exciting!"


	6. Chapter 6

**Summary for the Chapter:**

> Sherlock and John give Lestrade his new evidence.

**Notes for the Chapter:**

> Gah. I have no idea why it took me so long to finish this chapter. Apologies.

John's “date,” it turned out, was with a Mrs. Jenny Dorset, the victim's grieving widow. When John had first heard Sherlock's plan, which essentially boiled down to “John flirts with the widow under the pretense of checking on her while Sherlock searches the rest of the house,” he had been skeptical, and just a little queasy. Grieving widows were generally off-limits. But it turned out that Jenny Dorset didn't subscribe to the traditional method of grieving. Some people cried; some ate; others were stoic. Jenny Dorset looked for a replacement. It wasn't that she hadn't loved her husband; she had, dearly. It was more that she couldn't bear to be alone.

Under different circumstances, John might have been pleased by the coy looks Jenny Dorset was now shooting him from behind her tea cup. She was a beautiful woman, all charisma and wit. But John couldn't quite get past the special kind of awkwardness that comes from having dissected someone's dead husband. There was just no coming back from that. So John focused on talking with Jenny about what she planned to do now.

It seemed Sherlock approved at the rapport that John had built with the widow, because after a minute or two of watching the two flirt – one reluctantly, the other with gusto – the detective excused himself to take a non-existent phone call. Once out of the tastefully decorated sitting room, Sherlock quietly let himself into the locked study across the hall. He closed the door behind him and stood with his back to it for a moment, scanning the room, searching for useful data.

_Large room, ending in french doors onto a veranda and floor-to-ceiling windows. Deep red carpet, mahogany bookshelves lining the walls, crammed with books lined up like soldiers at the edge of the shelves. Law books, history, memoirs, literature – English, Italian, French – emphasis on the romantics. A large, solid desk at the end of the room, facing the windows. Mahogany as well. Locked drawers – careful and private, even in his own home. Good quality locks, but certainly not unpickable. Nothing unusual inside. No hidden compartments in the desk. Chair – high-backed, leather, padded. Mahogany frame, solid, no hidden compartments either. Pills must be in the bookshelves then._

_Books are lined up at edge of shelves rather than pushed back – creates pockets behind them. Not a brilliant hiding place, but just unexpected enough to be clever. Hiding place most likely to the right of the desk – Dorset was clearly right-handed. (It's clear by the set-up of the desk, but that data is superfluous – the coffee stains on the right leg of Dorset's trousers in Richardson's apartment had been clear enough. Dorset had been holding his coffee in his right hand when he spilled.)_

_Bookshelf to the immediate right of the desk: shelf at eye-level to Dorset? No, he was trying to be clever, so he would have chosen the shelf two below, at knee-level. British Romantic poetry. There, forth from the left. A collection of works by Lord Byron – quite fitting, given the purpose of the medication it's hiding. Behind it, a bottle of isocarboxazid – first generation MAOI. Prescription written by Dr. Anthony Richardson, made out to Jenny Dorset. Clever._

Sherlock re-entered the sitting room suddenly, closing the door with a noise somewhere between a crack and a thud. John and Mrs. Dorset turned to look at him, and the widow's face paled when she saw the bottle of medication the detective held aloft. “You didn't come here to check on me, did you?” It was clear she knew the answer. Sherlock smiled indulgently. “No, Mrs Dorset, we did not.” Jenny Dorset nodded slightly. “So I imagine you'll be wanting to know why there's a bottle of anti-depressants prescribed to me hidden in Tim's study,” she said, slowly this time. “If it's not too much trouble,” said Sherlock, more of his usual condescension creeping into his tone.

The widow nodded again, swallowed audibly, and paused, seemingly gathering her nerve. After a tense moment, she took a shaky breath and began. “It started about 4 years ago, when Tim and I had been dating for about a year. Tim sank into this horrible depression. He could barely get out of bed, and more than once he talked about killing himself. When he started hallucinating, he took a leave of absence from work.” John nodded in recognition. “Depression with psychotic features,” he said. Jenny Dorset nodded. “The worst kind,” she agreed.

“He was sure that if he went to the doctor, his firm would find out and he'd lose his job, or worse, be disbarred,” she continued. “He knew he was sick, but he refused to see anyone. I was terrified for him, so I went to Anthony – Dr. Richardson. He and I had stayed friends after we broke up, and he was happy for Tim and I when we got together. The two of them were very close.” She paused, twisting her wedding ring on her finger for a moment before speaking again. “I told Anthony what was going on, how Tim refused to see anyone, and we came up with a plan. If Anthony treated Tim under my name, Tim's career would be safe, but he could still get treatment. So Tim and I would go in for 'couples therapy,' and Anthony would put everything in my chart, not Tim's.”

Her tone began to hollow. Her clasped hands stilled in her lap, and she stared blankly at them. “We tried everything – SSRIs, tricyclic anti-depressants, SNRIs, atypical anti-psychotics as adjuncts. Nothing worked. Tim would get well enough that he wasn't psychotic or suicidal, but he was still horribly affected. So Anthony finally suggested we try MAOIs. We tried a newer one first, and it helped, but it still wasn't enough, so we tried that.” The widow gestured to the bottle in Sherlock's hand.

“It worked. The dietary restrictions were annoying, but Tim was finally himself again. So ever since then, Anthony's been prescribing Tim's medication to me.”Jenny Dorset finally looked up, meeting Sherlock's eyes. “And because of the dietary restrictions imposed by the medication, and the fact that it was your husband who adhered to these restrictions, not yourself, your husband kept his medication hidden – an extra precaution that would allow him to write off his restricted diet as mere food preferences,” concluded Sherlock. Jenny Dorset nodded.

“But why is this relevant?” she asked. “If Tim had a heart attack... oh.” John and Sherlock watched as a dark shadow of realization crept over her face. “It wasn't just a heart attack, was it?” Her voice was barely above a whisper now. “Because a heart attack, that's what would happen if Tim broke the diet. He was fastidious about it, he'd never do that, and if he had, you wouldn't be here.” She looked up from where she had been fidgeting with her wedding ring again. “So you think someone broke it for him.”

A smile ghosted on Sherlock's lips. “Very good. Have you worked out who it is?” Sherlock watched Jenny Dorset's face as she processed the information, watched her reach her conclusion, watched her heart break just a little more. “Anthony,” she whispered, looking off into space, stunned. “He was the only other person who knew, and Tim was with him when he died.” Her eyes were shiny with tears, but her upper-crust breeding would never allow them to fall. She turned her attention back to Sherlock. “The police told me the investigation was closed.”

“The police, as is often the case, do not have all the information,” Sherlock replied. “I am sure that, should what you've just told me be brought to their attention, they'd be more than happy to re-open it.” The widow nodded and swallowed hard. “I'll do it.”

Sherlock pulled out his mobile and pressed a button on the speed dial. “Hello, Lestrade? Yes, I've got someone here you're going to want to speak to.”

**Notes for the Chapter:**

> Aaaaaand we're done! I hope you all enjoyed it! I have an idea for my next fic, but it's going to be a long one, so I'm not going to start posting it until I have a good portion of it done. That way I won't suck at updating so much. 
> 
> *shuffles away awkwardly*


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